The Optic Nerve Crush Injury Paradigm in African Turquoise Killifish to Study Axonal Regeneration in an Aged Environment

In our graying world population, we are increasingly facing brain injuries and age-associated neurodegenerative diseases, which are often characterized by axonal pathology. Here, we propose the killifish visual/retinotectal system as a model for investigating central nervous system repair, more specifically axonal regeneration, in an aging context. We first describe an optic nerve crush (ONC) injury paradigm in killifish to induce and study both de- and regeneration of retinal ganglion cells (RGCs) and their axons. Subsequently, we summarize several methods for mapping different steps of the regenerative process-namely, axonal regrowth and synapse reformation-using retro- and anterograde tracing methods, (immuno)histochemistry, and morphometrical analyses.